Search for the pentaquark via the P-(c)over-bars(0)-> K*(0)K(-)p decay

We have searched for evidence of the production and decay of a neutral boun d-state pentaquark, one of a predicted doublet of states: P-(c over bar s)( 0) = \(c) over bar suud] and P-(c over bar s)(-) = \(c) over bar sddu]. Spe cifically, we have searched for the decay P-(c over bar s)(0) --> K *K-0(-) p in data from Fermilab experiment E791, in which a 500 GeV/c pi(-) beam i nteracted with nuclear targets. We find mass-dependent upper limits at the 90% confidence level for the ratio of cross section times branching fractio n of this decay relative to that for the decay D-s(-) --> K *K-0(-). The up per limits vary between 0.016 and 0.036 for M(P-(c over bar s)(0)) between 2.75 and 2.91 GeV/c(2), assuming a pentaquark lifetime of 0.4 ps. (C) 1999 Published by Elsevier Science B.V. All rights reserved.